The present invention relates generally to containers for housing medical solutions and means for accessing same. More specifically, the present invention relates to adaptors for receiving a cannula and maintaining same within a sterile environment and protectors for maintaining a sterile environment.
Housing medical solutions and products in flexible plastic containers is, of course, known. These containers provide a means for housing the solution prior to the solution being administered to a patient or used for other therapeutic applications.
Likewise, it is known to house a variety of solutions in such containers for a variety of medical procedures. Such solutions include intravenous, enteral, and peritoneal solutions. In this regard, flexible containers are used for peritoneal dialysis.
In peritoneal dialysis, a dialysis solution is introduced into a patient's peritoneal cavity utilizing a catheter. After a sufficient period of time, an exchange of solutes between the dialysate and the blood is achieved. Fluid removal is achieved by providing a suitable osmotic gradient from the blood to the dialysate to permit water outflow from the blood. This allows a proper acid-base, electrolyte and fluid balance to be returned to the blood. The dialysis solution is simply drained from the body cavity through the catheter.
In order to access the interior of a container, either to infuse solution therein or access a solution contained therein, it is known to provide containers with one or more ports or fitments. These ports are typically tubular in shape and define a flow path from an interior of the container to the outside environment.
Such ports may include a piercable membrane or injection site. In use, fluid is either added to the container or accessed therefrom by inserting a needle, cannula, or other member through the port piercing a membrane or an injection site.
To prevent contamination of the solution, and infection to the patient, the transfer of solution out of the container, and in many instances into the container, must take place under sterile conditions. Therefore, the distal ends of the port or connector (e.g., cannula, luer connector, etc.) are frequently capped with a "port protector." The function of the port protector is to preserve the sterile integrity of the interior of the port or connector after the entire container assembly has been assembled and terminally sterilized. Most frequently, sterilization in the medical industry is through the use of steam sterilization. Steam sterilization typically takes place under elevated temperatures and pressures, such as, for example, 120.degree. C. (250.degree. F.).
Currently, one method used to provide the necessary requirements of a port protector is to use a plastic sleeve, typically constructed from extruded flexible polyvinyl chloride, that is sealed off at one end with a slit opening cut along the longitudinal direction of the sleeve. During assembly, the sleeve is spread open at the slit and slipped onto the tube through the pre-slit opening. The sealed end is placed against the opening of the tube to provide the protective function. During steam sterilization, steam can penetrate through the sleeve so that a sufficient microbial kill is achieved. During use, ideally, the user or patient grabs the slit end of the sleeve and pulls it away from the tube to expose the tube for use.
Although these pre-slit sleeves have been in use for many years, a number of issues with respect to the use of same exist. For example, frequently, the sleeve develops a strong tack with the tube during steam sterilization. This can make it very difficult to remove.
Additionally, the thin walled slit part of the sleeve often becomes severely distorted during steam sterilization. This can make it extremely difficult for a patient with visual or manual impairment to remove the sleeve.
Still further, the dimensions of the flexible sleeve are difficult to control. Accordingly, relaxations of the material may occur during the steam sterilization process, causing the sleeve to come off at a later time, thereby breaching the sterile barrier.
Furthermore, during the extrusion manufacturing of the sleeve, die lines are frequently introduced in the longitudinal direction. This can reduce the sterile barrier, or at times, render the microbial barrier ineffective.
Additionally, sometimes in systems with closed ends, pressure differentials are created during sterilization. These pressure differentials can blow off the sleeve, destroying the sterile barrier.
One approach that has been used in an attempt to overcome the disadvantages of the sleeve is to use an injection molded cap to ensure the sterility of the surfaces under the protector cap. An example of such a cap is set forth in U.S. Pat. No. 4,572,980.
Injection sites which allow for the introduction of intraperitoneally administered drugs into a solution bag including the admixture of non-shelf stable nutrients and reconstituted medications are known. Prior injection sites, however, often are positioned at a distance from the solution bag requiring squeezing of the port tube to mix the drug.
Often, injection sites are small in cross-sectional areas such that a needle, cannula or other injection device, may not properly penetrate the injection site. As a result, accidental needle sticks of a user or misplaced injections through the injection site and/or other membrane often takes place. In addition, accidental puncturing of a wall of the solution bag often results.
A need, therefore, exists for an improved medication port, adaptor and protector for a container assembly, such as a solution bag used in peritoneal dialysis.